buildExpressionParser table term builds an expression parser for
terms term with operators from table, taking the associativity
and precedence specified in table into account. Prefix and postfix
operators of the same precedence can only occur once (i.e. --2 is
not allowed if - is prefix negate). Prefix and postfix operators
of the same precedence associate to the left (i.e. if ++ is
postfix increment, than -2++ equals -1, not -3).

The buildExpressionParser takes care of all the complexity
involved in building expression parser. Here is an example of an
expression parser that handles prefix signs, postfix increment and
basic arithmetic.